Self-damping actuator

ABSTRACT

The subject matter of this specification can be embodied in, among other things, an actuator apparatus includes an output member configured to actuate between a first positional configuration and a second positional configuration, a source fluid reservoir, a fluid velocity resistor configured to provide a predetermined resistance to fluid flow, a fluid velocity fuse configured to flow fluid flows having a first predetermined range of fluid velocities and to block fluid flows having second predetermined range of fluid velocities, and a fluid actuator assembly configured to urge fluid flow from the source fluid reservoir through the fluid velocity resistor and the fluid velocity fuse based on actuation of the output member.

TECHNICAL FIELD

This instant specification relates to an aircraft thrust reverseractuation system.

BACKGROUND

Thrust reversers are commonly incorporated in aircraft turbine engines.The role of the thrust reverser is to improve the braking capability ofthe aircraft upon landing by redirecting fluid flow through the engineto provide a counter-thrust opposing the direction of travel. As thethrust reverser is deployed, the forces that are being opposed act toaid in the deployment (e.g., as the reverser enters the airflow, theairflow urges the reverser toward its deployed position). In general, atthe start of deployment, energy is needed to actuate the reverser, butduring deployment the energy of the airflow can cause the actuator togenerate, rather than consume, energy.

Many current and past aircraft implement hydraulic thrust reverseractuation systems (HTRAS). In some such systems, the additionalhydraulic flow caused by aiding forces can place a large hydraulic flowdemand on the aircraft hydraulic pump. To limit flow demand,regenerative-type directional control valves are often utilized. Thesedirectional control valves permit fluid flowing from the retract or“stow” chambers of the actuators to be recirculated to the actuatordeploy chambers during deployment of the thrust reverser. Therecirculation flow can be selectively implemented as an external aidingload is applied to the actuators during deployment.

More recently, in some applications, HTRAS have been replaced byelectromechanical thrust reverser actuation systems (EMTRAS) in aircraftturbine engine applications. New reverser types such as the HiddenBlocker Door (HBD) and Sliding Cascade (SC) are also being used, howeverthese new types of reversers produce much larger loads upon theactuation system than conventional cascade type reversers. The highaiding loads can create unacceptably large loads upon the gear trains ofsuch actuators, and can produce unacceptably high amounts ofregenerative electrical power from the back-driving of the actuatormotors.

SUMMARY

In general, this document describes a thrust reverser actuation system.

In a general aspect, an actuator apparatus includes an output memberconfigured to actuate between a first positional configuration and asecond positional configuration, a source fluid reservoir, a fluidvelocity resistor configured to provide a predetermined resistance tofluid flow, a fluid velocity fuse configured to flow fluid flows havinga first predetermined range of fluid velocities and to block fluid flowshaving second predetermined range of fluid velocities, and a fluidactuator assembly configured to urge fluid flow from the source fluidreservoir through the fluid velocity resistor and the fluid velocityfuse based on actuation of the output member.

Various embodiments can include some, all, or none of the followingfeatures. The fluid velocity resistor can be connected in fluidicparallel with the fluid velocity fuse. The fluid actuator assembly caninclude a fluid piston assembly including a pressure chamber defined bythe source fluid reservoir and a piston configured to vary a volume ofthe pressure chamber based on actuation of the output member. Theactuator apparatus can also include a drain fluid reservoir, where thefluid velocity resistor and the fluid velocity fuse are connected influidic parallel between the pressure chamber and the drain fluidreservoir, and the fluid piston assembly is configured to urge fluidflow from the pressure chamber to the drain fluid reservoir through thefluid velocity resistor and the fluid velocity fuse. The drain fluidreservoir can include a fluid pressure assembly configured to urge fluidflow from the drain fluid reservoir to the source fluid reservoir. Thefluid pressure assembly can include a fluid chamber defined by the drainfluid reservoir and another piston configured to energize an energystorage member in response to receiving fluid from the fluid actuatorassembly, and to urge fluid flow toward the fluid actuator assemblybased on energy recovered from the energy storage member. The fluidactuator assembly can include a fluid pump assembly configured to bedriven by the output member. The fluid pump assembly can include a firstfluid port in fluidic communication with a first side of the fluidvelocity resistor and a first side of the fluid velocity fuse, a secondfluid port in fluidic communication with a second side of the fluidvelocity resistor and a second side of the fluid velocity fuse, a pumpmember configured to urge fluid flow from the first fluid port to thesecond fluid port, and to urge fluid flow from the second fluid port tothe first fluid port through the fluid velocity resistor and the fluidvelocity fuse. The actuator apparatus can also include anelectromechanical actuator configured to actuate the output member.

In another general aspect, a method of controlling actuator velocityincludes urging movement of an output member of an actuator at a firstoutput member velocity, urging, by a fluid actuator assembly, based onmovement of the output member at the first output member velocity, fluidflow at a first fluid flow velocity through a fluid velocity resistorconfigured to provide a predetermined resistance to fluid flow, urging,by the fluid actuator assembly, based on movement of the output memberat the first output member velocity, fluid flow at a second fluid flowvelocity through a fluid velocity fuse configured to flow fluid flowshaving a first predetermined range of fluid velocities and to blockfluid flows having second predetermined range of fluid velocities,wherein the second fluid flow velocity is within the first predeterminedrange of fluid velocities, permitting, by the fluid velocity fuse, fluidflow through the fluid velocity fuse based on the second fluid flowvelocity being within the first predetermined range of fluid velocities,urging movement of the output member at a second output member velocity,different from the first output member velocity, urging, by a fluidactuator assembly, based on movement of the output member at the secondoutput member velocity, fluid flow at a third fluid flow velocitythrough the fluid velocity resistor, and urging, by the fluid actuatorassembly, based on movement of the output member at the second outputmember velocity, fluid flow at a fourth fluid flow velocity through thefluid velocity fuse, wherein the fourth fluid flow velocity is differentfrom the second fluid flow velocity, and wherein the fourth fluid flowvelocity is within the second predetermined range of fluid velocities,and blocking, by the fluid velocity fuse, fluid flow through the fluidvelocity fuse based on the fourth fluid flow velocity being within thesecond predetermined range of fluid velocities.

Various implementations can include some, all, or none of the followingfeatures. The method can also include resisting movement of the outputmember at a first level of resistance based on the first fluid flowvelocity and the second fluid flow velocity, and resisting movement ofthe output member at a first level of resistance based on the thirdfluid flow velocity and based on the blocking of fluid flow by the fluidvelocity fuse. The fluid velocity resistor can be connected in fluidicparallel with the fluid velocity fuse. The fluid actuator assembly caninclude a fluid piston assembly having a pressure chamber defined by asource fluid reservoir and a piston configured to vary a volume of thepressure chamber based on actuation of the output member, urging, by thefluid actuator assembly, based on movement of the output member at thefirst output member velocity, fluid flow at the first fluid flowvelocity through the fluid velocity resistor configured to provide thepredetermined resistance to fluid flow also includes reducing the volumeof the pressure chamber, based on movement of the output member at thefirst output member velocity and urging fluid flow out of the pressurechamber at a first outflow rate, and urging, by the fluid actuatorassembly, based on movement of the output member at the second outputmember velocity, fluid flow at the fourth fluid flow velocity throughthe fluid velocity fuse, where the fourth fluid flow velocity isdifferent from the second fluid flow velocity, and where the fourthfluid flow velocity is within the second predetermined range of fluidvelocities also includes reducing the volume of the pressure chamber,based on movement of the output member at the second output membervelocity and urging fluid flow out of the pressure chamber at a secondoutflow rate that is different from the first outflow rate. The methodcan also include urging fluid flow to a drain fluid reservoir, whereinthe fluid velocity resistor and the fluid velocity fuse are connected influidic parallel between the pressure chamber and the drain fluidreservoir, and the fluid piston assembly is configured to urge fluidflow from the pressure chamber to the drain fluid reservoir through thefluid velocity resistor and the fluid velocity fuse. The method can alsoinclude urging, by a fluid pressure assembly of the pressure chamber,fluid flow from the drain fluid reservoir to the source fluid reservoir.The method can also include energizing an energy storage member based onfluid flow to the drain fluid reservoir, and wherein urging, by thefluid pressure assembly of the pressure chamber, fluid flow from thedrain fluid reservoir to the source fluid reservoir can include urgefluid flow toward the fluid actuator assembly based on energy recoveredfrom the energy storage member. The method can also include pumping, bya fluid pump assembly of the fluid actuator assembly and configured tobe driven by the output member, fluid at a first pump output velocitybased on movement of the output member at the first output membervelocity, wherein the first fluid flow velocity and the second fluidflow velocity are based on the first pump output velocity, and pumping,by the fluid pump assembly, fluid at a second pump output velocitydifferent from the first pump output velocity based on movement of theoutput member at the second output member velocity, wherein the thirdfluid flow velocity and the fourth fluid flow velocity are based on thesecond pump output velocity. The method can also include urging, by apump member of the fluid pump assembly, fluid from a first fluid port influidic communication with a first side of the fluid velocity resistorand a first side of the fluid velocity fuse, to a second fluid port influidic communication with a second side of the fluid velocity resistorand a second side of the fluid velocity fuse, and urging, by the pumpmember, fluid flow from the second fluid port to the first fluid portthrough the fluid velocity resistor and the fluid velocity fuse. Themethod can also include applying electric power to an electromechanicalactuator configured to urge movement of the output member.

In another example aspect, a turbofan engine system includes a turbofanengine, a nacelle surrounding the turbofan engine and defining anannular bypass duct through the turbofan engine to define a generallyforward-to-aft bypass air flow path, a thrust reverser having at leastone output member, movable to and from a reversing position where atleast a portion of bypass air flow is reversed, an actuator coupled tothe at least one output member to move the at least one output memberinto and out of the reversing position, a source fluid reservoir, afluid velocity resistor configured to provide a predetermined resistanceto fluid flow, a fluid velocity fuse configured to flow fluid flowshaving a first predetermined range of fluid velocities and to blockfluid flows having second predetermined range of fluid velocities, and afluid actuator assembly configured to urge fluid flow from the sourcefluid reservoir through the fluid velocity resistor and the fluidvelocity fuse based on actuation of the output member.

The systems and techniques described here may provide one or more of thefollowing advantages. First, a system can reduce or eliminate electricalresistor banks used to dissipate electrical energy that is regeneratedwhen the system is under high tension load. Second, the system canimprove the reliability or mean time between failure (MTBF) of thesystem by reducing or eliminating electrical resistor banks and thepotential failure points associated with them. Third, the system canprovide a damping apparatus with reduced weight by reducing oreliminating electrical resistor banks and the weight associated withthem. Fourth, the system can reduce the amount of space or operationalenvelope used to provide damping functions by reducing the space neededfor resistor banks. Fifth, the system can provide improved operatorsafety by reducing or eliminating resistor banks that can become hotafter usage and must be allowed to cool before maintenance can be safelyperformed on the reverser.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will be apparent from the description and drawings, and fromthe claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of an example turbofan jet engine system witha portion of the outer nacelle cut away for clarity.

FIG. 2 is a schematic view of the engine of FIG. 1 with an exemplarythrust reverser.

FIG. 3 is a schematic view of the engine of FIG. 1 with an alternativeexemplary thrust reverser.

FIGS. 4A and 4B are cross-sectional views of an example thrust reversersystem with velocity control.

FIG. 5 is a cross-sectional view of another example thrust reversersystem with velocity control.

FIG. 6 is a cross-sectional view of another example thrust reversersystem with velocity control.

FIG. 7A is a cross-sectional view of another example thrust reversersystem with velocity control.

FIGS. 7B and 7C are cross-sectional views of another example thrustreverser velocity controller.

FIG. 8 is a flow diagram of an example process for thrust reversersystem velocity control.

DETAILED DESCRIPTION

This document describes thrust reverser actuation systems (TRAS). Inmost thrust reverser actuation systems, the external load imposed by thereverser during deployment upon the TRAS changes from compression totension after an initial push-off load in compression. The tension loadcan become very high with advanced technology thrust reversers. In aconventional electromechanical TRAS (EMTRAS), the force-times-distanceenergy of the aiding load is first imposed upon the actuator gear trainwhich in tum back-drives the electric motor. The motor must thendissipate this energy as heat through a bank of resistors.

With advanced technology thrust reversers the aiding loads will resultin large loads transmitted through the gear teeth. This loading willnecessitate commensurate upsizing of the gear teeth and other componentsto ensure adequate performance over life. This will have unacceptablesize and weight consequences for the EMTRAS. The aiding load causes theEMTRAS electric motor to act as a generator (regenerative power). Thisregenerative power must be dissipated as heat in a bank of electricalresistors. The large amperages applied to the resistors result in lowreliability for the affected resistors. In general, the systems andtechniques described in this document reduce gear loading and theregenerative power of aiding forces to reasonable levels, by providinghydraulic damping in the actuator to reduce loads upon the gear trainand electric motor.

FIG. 1 is a schematic view of an example turbofan jet engine system.FIG. 1 illustrates an example turbofan jet engine assembly 10 having aturbine engine 12, a fan assembly 13, and a nacelle 14. Portions of thenacelle 14 have been cut away for clarity. The nacelle 14 surrounds theturbine engine 12 and defines an annular airflow path or annular bypassduct 16 through the jet engine assembly 10 to define a generallyforward-to-aft bypass airflow path for bypass air flow as schematicallyillustrated by the arrow 18. A combustion airflow is schematicallyillustrated by the arrows 19.

A thrust reverser with at least one movable element, which is movable toand from a reversing position, may be used to change the direction ofthe bypass airflow. In the reversing position, the movable element maybe configured to reverse at least a portion of the bypass airflow. Thereare several methods of obtaining reverse thrust on turbofan jet engineassemblies. FIG. 2 schematically illustrates one example of a thrustreverser 20 that may be used in the turbofan jet engine assembly 10. Thethrust reverser 20 includes a movable element 22. The movable element 22has been illustrated as a cowl portion that is capable of axial motionwith respect to the forward portion of the nacelle 14. Anelectromechanical actuator 24 may be coupled to the movable element 22to move the movable element 22 into and out of the reversing position.In the reversing position, as illustrated, the movable element 22 limitsthe annular bypass area between the movable element 22 and the turbineengine 12, it also opens up a portion 26 between the movable element 22and the forward portion of the nacelle 14 such that the air flow pathmay be reversed as illustrated by the arrows 28. An optional deflectoror flap 29 may be included to aid in directing the airflow path betweenthe movable element 22 and the forward portion of the nacelle 14.

FIG. 3 schematically illustrates an alternative example of a thrustreverser 30. The thrust reverser 30 includes a movable element 32. Themovable element 32 has been illustrated as a deflector, which may bebuilt into a portion of the nacelle 14. An electromechanical actuator 34may be coupled to the movable element 32 to move the movable element 32into and out of the reversing position. In the reversing position, shownin phantom and indicated at 36, the movable element 32 turns that airoutward and forward to reverse its direction as illustrated by thearrows 38. An optional deflector or flap 39 may be included to aid indirecting the airflow path outward.

In both illustrative examples, the thrust reverser changes the directionof the thrust force. Both the thrust reverser 20 and the thrust reverser30 have been described as electrically operated systems and anelectromechanical actuator has been schematically illustrated. In someembodiments, the thrust reverser 20 and/or the thrust reverser 30 can bepowered by fluids (e.g., hydraulic, pneumatic) or by any otherappropriate power source or actuator type.

FIGS. 4A and 4B are cross-sectional views of an example thrust reversersystem (TRAS) 400 with velocity control. The TRAS 400 is an actuatorapparatus that includes a linear actuator 410 that is driven by anelectromechanical power source, and an electric motor 412. As such, theTRAS 400 is an electromechanical TRAS (EMTRAS). In some embodiments, thelinear actuator 410 can be the electromechanical actuator 24 of FIG. 2or the electromechanical actuator 34 of FIG. 3.

The linear actuator 410 is driven by the electric motor 412 through asynchronization shaft 414. A gearbox 416 transforms rotation of thesynchronization shaft 414 to rotation of an output member 418 and a nut420. In some embodiments, the electric motor 412 can be integrated withthe linear actuator 410 to drive rotation of the nut 420.

The linear actuator 410 includes an output member 430 configured toactuate between a first positional configuration and a second positionalconfiguration. The output member 430 includes a leadscrew 432 configuredto be driven linearly by rotation of the nut 420. As the nut 420 isrotated clockwise and counter-clockwise, the output member 430 extends(e.g., toward a deployed configuration of the TRAS 400) and retracts(e.g., toward a retracted or stowed configuration of the TRAS 400).

The linear actuator 410 includes a fluid actuator assembly 440. Thefluid actuator assembly 440 includes a source fluid reservoir 434 and afluid piston assembly 441. The fluid actuator assembly 440 has apressure chamber 442 defined by the source fluid reservoir 434, and thefluid piston assembly 441 includes a piston 444 configured to vary avolume of the pressure chamber 442 based on actuation of the outputmember 430. The piston 444 is affixed to and configured to be driven bythe output member 430, and linear movement of the output member 430varies the volume of the source fluid reservoir 434. As the volume ofthe source fluid reservoir 434 varies, fluid (e.g., hydraulic fluid) isurged bidirectionally through a fluid port 450. The fluid velocity atwhich the fluid flows through the fluid port 450 is variable andproportional to the linear velocity of movement of the output member430.

The source fluid reservoir 434 is in fluid communication with a drainfluid reservoir 460 through a fluid velocity resistor 470 configured toprovide a predetermined resistance to fluid flow, and a fluid velocityfuse 480. The fluid velocity resistor 470 and the fluid velocity fuse480 are connected in fluidic parallel between the pressure chamber 442and the drain fluid reservoir 460.

The fluid velocity fuse 480 is configured to flow fluid flows having afirst predetermined range of fluid velocities and to block fluid flowshaving second predetermined range of fluid velocities. For example, whenfluid flows through the fluid velocity fuse 480 from the source fluidreservoir 434 toward the drain fluid reservoir 460 at or below apredetermined fluid velocity threshold, the flow is permitted. However,when the fluid flow through the fluid velocity fuse 480 toward the drainfluid reservoir 460 exceeds the predetermined fluid velocity threshold,the fluid velocity fuse 480 will shut and block flow until the velocitydrops below the predetermined velocity threshold again. Fluid flowthrough the fluid velocity fuse 480 in the opposite direction issubstantially unaffected regardless of velocity.

In the example of FIG. 4A, the TRAS 400 is shown in a configuration inwhich the fluid velocity fuse 480 is open (e.g., untriggered). In someimplementations, this configuration can exist when the output member 430is extending at a velocity that is at or below a predetermined thresholdvelocity, or is retracting. For example, the illustrated configurationof FIG. 4A can represent the configuration of the TRAS 400 during earlystages of thrust reverser deployment, when the linear actuator 410provides most or all of the power needed to deploy the thrust reverser(e.g., before engine thrust catches the thrust reverser and providesadditional power that can increase the rate of deployment).

As the output member 430 extends, the fluid piston assembly 441 urgesfluid flow from the pressure chamber 442 to the drain fluid reservoir460 through the fluid velocity resistor 470 and the fluid velocity fuse480. The drain fluid reservoir 460 includes a fluid pressure assembly462 configured to urge fluid flow from the drain fluid reservoir 460 tothe source fluid reservoir 434.

The fluid pressure assembly 462 includes a fluid chamber 464 defined bythe drain fluid reservoir 460 and a piston 466 configured to energize anenergy storage member 468 in response to receiving fluid from the fluidactuator assembly 440, and to urge fluid flow toward the fluid actuatorassembly 440 based on energy recovered from the energy storage member468. As fluid enters the fluid chamber 464, the piston 466 moves. In theillustrated example, the energy storage member 468 is a spring oranother type of compliant member that can be distorted (e.g.,compressed) by movement of the piston 466. When incoming fluid pressuredrops, the spring can return toward its undistorted shape, urgingmovement of the piston 466 and return flow of the fluid.

In some embodiments, the fluid pressure assembly 462 can have any otherappropriate configuration that can provide return flow of the fluid. Forexample, the fluid pressure assembly 462 can be an elastic bladder thatcan be inflated by inflow and cause outflow upon deflation. In anotherexample, the fluid pressure assembly 462 can include a volume ofcompressible fluid (e.g., air) that can be compressed by inflow of theincompressible fluid and cause outflow upon decompression. In anotherexample, the fluid pressure assembly 462 can be a chamber positioned atan elevated level relative to the source fluid reservoir 434 (e.g.,fluid can be urged upward relative to gravity, and then be gravity-fedback to the source). In some embodiments, the fluid pressure assembly462 can include an electric or mechanical pump configured to urge returnflow.

In the example of FIG. 4B, the TRAS 400 is shown in a configuration inwhich the fluid velocity fuse 480 is closed (e.g., shut, triggered). Insome implementations, this configuration can exist when the outputmember 430 is extending at a velocity that exceeds the predeterminedthreshold velocity. For example, the illustrated configuration of FIG.4B can represent the configuration of the TRAS 400 during later stagesof thrust reverser deployment, when reversed thrust causes the thrustreverser to pull on the output member 430, causing a sudden increase thevelocity of extension of the output member 430 and an increase in therate of deployment of the thrust reverser.

In the illustrated configuration, since the fluid velocity fuse 480 isclosed, substantially all flow of fluid from the source fluid reservoir434 toward the drain fluid reservoir 460 is directed through the fluidvelocity resistor 470. The fluid velocity resistor 470 reduces thevelocity of the flow, which in turn reduces the velocity at which fluidis able to exit the source fluid reservoir 434, which in turn reducesthe velocity at which the output member 430 can move.

FIG. 5 is a cross-sectional view of another example thrust reversersystem (TRAS) 500 with velocity control. The TRAS 500 is an actuatorapparatus that includes a linear actuator 510 that is driven by theelectric motor 412. As such, the TRAS 500 is an electromechanical TRAS(EMTRAS). In some embodiments, the linear actuator 510 can be theelectromechanical actuator 24 of FIG. 2 or the electromechanicalactuator 34 of FIG. 3.

The linear actuator 510 is driven by the electric motor 412 through thesynchronization shaft 414. The gearbox 416 transforms rotation of thesynchronization shaft 414 to rotation of the output member 418 and thenut 420. In some embodiments, the electric motor 412 can be integratedwith the linear actuator 510 to drive rotation of the nut 420. Thelinear actuator 510 includes the output member 430 configured to actuatebetween a first positional configuration and a second positionalconfiguration.

The linear actuator 510 includes a piston assembly 540 having a pressurechamber 542 that defines a source fluid reservoir 534, and has a piston544 that is configured to be mechanically actuated based on movement ofthe output member 430. As the output member 430 moves, the piston 544moves to vary a volume of the pressure chamber 542. The piston 544 isaffixed to the output member 430 by a linkage 546 and is configured tobe driven by the output member 430, and linear movement of the outputmember 430 varies the volume of the source fluid reservoir 534. As thevolume of the source fluid reservoir 534 varies, fluid (e.g., hydraulicfluid) is urged bidirectionally through a fluid port 550. The fluidvelocity at which the fluid flows through the fluid port 550 is variableand proportional to the linear velocity of movement of the output member430.

The source fluid reservoir 534 is in fluid communication with the drainfluid reservoir 460 through the fluid velocity resistor 470 and thefluid velocity fuse 480. The fluid velocity resistor 470 and the fluidvelocity fuse 480 are connected in fluidic parallel between the pressurechamber 542 and the drain fluid reservoir 460.

As the output member 430 extends and retracts, the piston assembly 540urges fluid flow between the pressure chamber 542 to the drain fluidreservoir 460 through the fluid velocity resistor 470 and the fluidvelocity fuse 480. As in the examples shown in FIGS. 4A and 4B, thefluid velocity fuse 480 is configured to close when fluid flow towardthe drain fluid reservoir 460 exceeds a predetermined fluid velocity.When fluid velocity is limited, the velocity at which the piston 544 andthe output member 430 move are also limited.

FIG. 6 is a cross-sectional view of another example thrust reversersystem (TRAS) 600 with velocity control. The TRAS 600 is an actuatorapparatus that includes a linear actuator 610 that is driven by theelectric motor 412. As such, the TRAS 600 is an electromechanical TRAS(EMTRAS). In some embodiments, the linear actuator 610 can be theelectromechanical actuator 24 of FIG. 2 or the electromechanicalactuator 34 of FIG. 3.

The linear actuator 610 is driven by the electric motor 412 through thesynchronization shaft 414. The gearbox 416 transforms rotation of thesynchronization shaft 414 to rotation of the output member 418 and thenut 420. In some embodiments, the electric motor 412 can be integratedwith the linear actuator 610 to drive rotation of the nut 420. Thelinear actuator 610 includes the output member 430 configured to actuatebetween a first positional configuration and a second positionalconfiguration.

The linear actuator 610 includes a fluid actuator assembly 640. Thefluid actuator assembly 640 includes a source fluid reservoir 634, adrain fluid reservoir 660, and a fluid piston assembly 641. The fluidactuator assembly 640 has a pressure chamber 642 and a pressure chamber664 defined by the source fluid reservoir 634, and the fluid pistonassembly 641 includes a piston 644 configured to vary a volume of thepressure chamber 642 based on actuation of the output member 430. Thepiston 644 is also configured to vary the volume of the pressure chamber664 inversely relative to the volume of the pressure chamber 642 as theoutput member 430 moves. The piston 644 is affixed to and configured tobe driven by the output member 430, and linear movement of the outputmember 430 varies the volume of the source fluid reservoir 634 and thedrain fluid reservoir 660. As the volume of the source fluid reservoir634 and the drain fluid reservoir 660 vary, fluid (e.g., hydraulicfluid) is urged bidirectionally through a fluid port 650. The fluidvelocity at which the fluid flows through the fluid port 650 is variableand proportional to the linear velocity of movement of the output member430.

The source fluid reservoir 634 is in fluid communication with the drainfluid reservoir 660 through the fluid velocity resistor 470 and thefluid velocity fuse 480. The fluid velocity resistor 470 and the fluidvelocity fuse 480 are connected in fluidic parallel between the pressurechamber 642 and the drain fluid reservoir 660.

As the output member 430 extends and retracts, the piston assembly 640urges fluid flow between the pressure chamber 642 to the drain fluidreservoir 660 through the fluid velocity resistor 470 and the fluidvelocity fuse 480. The fluid velocity fuse 480 is configured to closewhen fluid flow toward the drain fluid reservoir 660 exceeds apredetermined fluid velocity. When fluid velocity is limited, thevelocity at which the piston 644 and the output member 430 move are alsolimited.

FIG. 7A is a cross-sectional view of another example thrust reversersystem (TRAS) 700 with velocity control. The TRAS 700 is an actuatorapparatus that includes a linear actuator 710 that is driven by theelectric motor 412. As such, the TRAS 700 is an electromechanical TRAS(EMTRAS). In some embodiments, the linear actuator 710 can be theelectromechanical actuator 24 of FIG. 2 or the electromechanicalactuator 34 of FIG. 3.

The linear actuator 710 is driven by the electric motor 412 through thesynchronization shaft 414. The gearbox 416 transforms rotation of thesynchronization shaft 414 to rotation of the output member 418 and thenut 420. In some embodiments, the electric motor 412 can be integratedwith the linear actuator 510 to drive rotation of the nut 420. Thelinear actuator 510 includes the output member 430 configured to actuatebetween a first positional configuration and a second positionalconfiguration.

The TRAS 700 includes a fluid velocity controller 701 a and a fluidvelocity controller 701 b. In some embodiments, the TRAS 700 may includeone or both of the fluid velocity controllers 701 a and 701 b. The fluidvelocity controllers 701 a and 701 b include a drive shaft 702 that isconfigured to be rotated, directly or indirectly, by the linear actuator710. In the illustrated example, the fluid velocity controller 701 a isdriven by rotation of the motor 412 (e.g., back-driven by motion of theoutput member 430), and the fluid velocity controller 701 b is driven bya pinion gear 703 that is rotated by linear movement of a correspondingrack gear 704 that is affixed to the output member 430. In someembodiments, one or both of the fluid velocity controllers 701 a and 701b can be driven by the linear actuator 710 in other ways. For example,one or both of the fluid velocity controllers 701 a and 701 b can bedirectly coupled to the motor 412, or can be coupled to thesynchronization shaft 414. In another example, one or both of the fluidvelocity controllers 701 a and 701 b can be magnetically coupled to amoveable or rotatable member of the TRAS 700.

FIGS. 7A and 7B are cross-sectional views of an example thrust reverservelocity controller 705. In some embodiments, the thrust reverservelocity controller 705 can be used as one or both of the example fluidvelocity controller 701 a and the example fluid velocity controller 701b. The velocity controller 705 includes the fluid velocity resistor 470and the fluid velocity fuse 480 of FIGS. 4A-6. The fluid velocityresistor 470 and the fluid velocity fuse 480 are connected in parallelbetween a fluid port 760 and a fluid port 762.

The thrust reverser velocity controller 705 also includes a fluid pumpassembly 750 (e.g., a pump member). The fluid pump assembly 750 includesthe drive shaft 702 that is configured to be rotated to urge rotation ofone or both of a pump gear 754 and a pump gear 756. The drive shaft 702is configured to be driven, directly or indirectly, by an output memberof a TRAS (e.g., the output member 430 or the synchronization shaft414).

The fluid pump assembly 750 includes a fluid port 751 in fluidiccommunication with the fluid port 760. As such, the fluid port 751 is influid communication with a first side 770 a of the fluid velocityresistor 470 and a first side 770 b of the fluid velocity fuse 480. Thefluid pump assembly 750 also includes a fluid port 752 in fluidiccommunication with the fluid port 762. As such, the fluid port 752 is influid communication with a second side 772 a of the fluid velocityresistor 470 and a second side 772 b of the fluid velocity fuse 480. Thefluid pump assembly 750 is configured to urge fluid flow from the fluidport 751 to the fluid port 752, and to urge fluid flow from the fluidport 752 to the fluid port 751 through the fluid velocity resistor 470and the fluid velocity fuse 480.

In the example of FIG. 7B, the thrust reverser velocity controller 705is shown in a configuration in which the fluid velocity fuse 480 is open(e.g., untriggered). In some implementations, this configuration canexist when the output member 430 is extending at a velocity that is ator below a predetermined threshold velocity, or is retracting. Forexample, the illustrated configuration of FIG. 7B can represent theconfiguration of the TRAS 700 during early stages of thrust reverserdeployment, when the linear actuator 410 provides most or all of thepower needed to deploy the thrust reverser (e.g., before engine thrustcatches the thrust reverser and provides additional power that canincrease the rate of deployment).

FIG. 7C shows the thrust reverser velocity controller 705 in aconfiguration in which the fluid velocity fuse 480 is closed (e.g.,triggered, tripped). In some implementations, this configuration canexist when the output member 430 is extending at a velocity that exceedsthe predetermined threshold velocity. For example, the illustratedconfiguration of FIG. 7C can represent the configuration of the TRAS 700during later stages of thrust reverser deployment, when engine thrustcatches the thrust reverser and provides additional power that canincrease the rate of deployment the linear actuator 410.

FIG. 8 is a flow diagram of an example process 800 for thrust reversersystem velocity control. In some implementations, the example processcan be performed by parts or all of one or more of the an exampleturbofan jet engine assembly 10 of FIGS. 1-3, the example thrustreverser 20, the example thrust reverser 30, the example TRAS 400 ofFIGS. 4A-4B, the example TRAS 500 of FIG. 5, the example TRAS 600 ofFIG. 6, the example TRAS 700 of FIG. 7A, and the example thrust reverservelocity controller 705 of FIGS. 7B and 7C for controlling actuatorvelocity.

At 805, movement of an output member of an actuator at a first outputmember velocity is urged. For example, the example output member 430 canbe extended at a first velocity based on power provided by the motor412.

At 810, fluid flow is urged, by a fluid actuator assembly and based onmovement of the output member at the first output member velocity, at afirst fluid flow velocity through a fluid velocity resistor configuredto provide a predetermined resistance to fluid flow. For example,movement of the example output member 430 urges actuation of the fluidpiston assembly 440, which causes a fluid flow out the fluid port 450 ata fluid velocity that is proportional to the linear velocity of theoutput member 430, and a portion of that flow flows though the fluidvelocity resistor 470.

At 815, fluid flow is urged, by the fluid actuator assembly and based onmovement of the output member at the first output member velocity, at asecond fluid flow velocity through a fluid velocity fuse configured toflow fluid flows having a first predetermined range of fluid velocitiesand to block fluid flows having second predetermined range of fluidvelocities, where the second fluid flow velocity is within the firstpredetermined range of fluid velocities. For example, movement of theexample output member 430 urges actuation of the fluid piston assembly441, which causes a fluid flow out the fluid port 450 at a fluidvelocity that is proportional to the linear velocity of the outputmember 430, and a portion of that flow flows to the fluid velocity fuse480.

At 820, the fluid velocity fuse permits fluid flow through the fluidvelocity fuse based on the second fluid flow velocity being within thefirst predetermined range of fluid velocities. For example, the portionof the flow that flows though the example fluid velocity fuse 480 cancontinue as long as that portion flows at a velocity that is not highenough to trip the fluid velocity fuse 480.

At 850, movement of the output member of the actuator at a second outputmember velocity is urged, and the second output member velocity isdifferent from the first output member velocity. For example, theexample output member 430 can be extended at a second (e.g., higher)velocity based on power provided by the motor 412 plus aiding forcesthat act upon the thrust reverser to draw the output member 430 intoextension faster than the rate that would be caused by the motor 412alone.

At 855, fluid flow is urged, by the fluid actuator assembly and based onmovement of the output member at the second output member velocity, at athird fluid flow velocity through the fluid velocity resistor configuredto provide the predetermined resistance to fluid flow. For example,movement of the example output member 430 urges actuation of the fluidpiston assembly 441, which causes a fluid flow out the fluid port 450 ata fluid velocity that is proportional to the linear velocity of theoutput member 430, and a portion of that flow flows though the fluidvelocity resistor 470.

At 860, fluid flow is urged, by the fluid actuator assembly and based onmovement of the output member at the second output member velocity, at afourth fluid flow velocity through the fluid velocity fuse configured toflow fluid flows having a first predetermined range of fluid velocitiesand to block fluid flows having second predetermined range of fluidvelocities. The fourth fluid flow velocity is different from the secondfluid flow velocity, and the fourth fluid flow velocity is within thesecond predetermined range of fluid velocities. For example, movement ofthe example output member 430 urges actuation of the fluid pistonassembly 440, which causes a fluid flow out the fluid port 450 at afluid velocity that is proportional to the linear velocity of the outputmember 430, and a portion of that flow is in fluid communication withthe fluid velocity fuse 480.

At 865, the fluid velocity fuse blocks fluid flow through the fluidvelocity fuse based on the fourth fluid flow velocity being within thesecond predetermined range of fluid velocities. For example, when thevelocity of fluid flowing through the example fluid velocity fuse 480exceeds a predetermined rating of the fluid velocity fuse 480, the fluidvelocity fuse 480 will close and block further fluid flow through thefluid velocity fuse 480. Under such conditions, substantially all of theflow is directed through the fluid velocity resistor 470.

In some implementations, the process 800 can include resisting movementof the output member at a first level of resistance based on the firstfluid flow velocity and the second fluid flow velocity, and resistingmovement of the output member at a first level of resistance based onthe third fluid flow velocity and the blocking of fluid flow by thefluid velocity fuse. For example, when the example output member 430 ismoving slowly, part of the fluid flow can pass through the fluidvelocity fuse 480 in parallel with the flow passing through the fluidvelocity resistor, but when the output member 430 is moving quicklyenough, the fluid velocity fuse 480 will close and cause additionalresistance to the flow and the mechanical forces that cause the flow.

In some implementations, the fluid velocity resistor can be connected influidic parallel with the fluid velocity fuse. For example, the examplefluid velocity resistor 470 is connected in fluidic parallel with thefluid velocity fuse 480.

In some implementations, the fluid actuator assembly of the process 800can include a fluid piston assembly having a pressure chamber defined bya source fluid reservoir and a piston configured to vary a volume of thepressure chamber based on actuation of the output member. In someimplementations, urging fluid flow at the first fluid flow velocitythrough the fluid velocity resistor can include reducing the volume ofthe pressure chamber, based on movement of the output member at thefirst output member velocity and urging fluid flow out of the pressurechamber at a first outflow rate. In some implementations, the urging caninclude urging, by the fluid actuator assembly, based on movement of theoutput member at the second output member velocity, fluid flow at thefourth fluid flow velocity through the fluid velocity fuse. In someimplementations, the fourth fluid flow velocity can be different fromthe second fluid flow velocity. In some implementations, the fourthfluid flow velocity being within the second predetermined range of fluidvelocities can include reducing the volume of the pressure chamber,based on movement of the output member at the second output membervelocity and urging fluid flow out of the pressure chamber at a secondoutflow rate that is different from the first outflow rate. For example,the example piston 444 can vary the volume of the pressure chamber 442based on actuation of the output member 430. In another example, thepiston 544 can move to vary a volume of the pressure chamber 542.

The process 800 can also include urging fluid flow to a drain fluidreservoir, wherein the fluid velocity resistor and the fluid velocityfuse are connected in fluidic parallel between the pressure chamber andthe drain fluid reservoir, and the piston assembly is configured to urgefluid flow from the pressure chamber to the drain fluid reservoirthrough the fluid velocity resistor and the fluid velocity fuse. Forexample, the example source fluid reservoir 434 can be in fluidcommunication with the example drain fluid reservoir 460 through thefluid velocity resistor 470 and the fluid velocity fuse 480.

The process 800 can also include urging, by a fluid pressure assembly ofthe pressure chamber, fluid flow from the drain fluid reservoir to thesource fluid reservoir. In some implementations, the process 800 caninclude energizing an energy storage member based on fluid flow to thedrain fluid reservoir, and wherein urging, by the fluid pressureassembly of the pressure chamber, fluid flow from the drain fluidreservoir to the source fluid reservoir comprises urge fluid flow towardthe fluid actuator based on energy recovered from the energy storagemember. For example, the example piston 466 can be configured toenergize the energy storage member 468 in response to receiving fluidfrom the fluid actuator assembly 440, and can urge fluid flow toward thefluid actuator assembly 440 based on energy recovered from the energystorage member 468.

In some implementations, the process 800 can include pumping, by a fluidpump assembly of the fluid actuator assembly and configured to be drivenby the output member, fluid at a first pump output velocity based onmovement of the output member at the first output member velocity,wherein the first fluid flow velocity and the second fluid flow velocityare based on the first pump output velocity, pumping, by the fluid pumpassembly, fluid at a second pump output velocity different from thefirst pump output velocity based on movement of the output member at thesecond output member velocity, wherein the third fluid flow velocity andthe fourth fluid flow velocity are based on the second pump outputvelocity. For example, the example fluid velocity controller 701 aand/or the example fluid velocity controller 701 b can be driven bymotion of the output member 430 to pump fluid through one or both of thefluid velocity resistor 470 and the fluid velocity fuse 480.

In some implementations, the process 800 can include urging, by a pumpmember of the fluid pump assembly, fluid from a first fluid port influidic communication with a first side of the fluid velocity resistorand a first side of the fluid velocity fuse, to a second fluid port influidic communication with a second side of the fluid velocity resistorand a second side of the fluid velocity fuse, urging, by the pumpmember, fluid flow from the second fluid port to the first fluid portthrough the fluid velocity resistor and the fluid velocity fuse. Forexample, the example fluid pump assembly 750 of FIGS. 7B and 7C includesthe fluid port 751 in fluidic communication with the fluid port 760. Assuch, the fluid port 751 is in fluid communication with the first side770 a of the fluid velocity resistor 470 and the first side 770 b of thefluid velocity fuse 480. The fluid pump assembly 750 also includes thefluid port 752 in fluidic communication with the fluid port 762. Assuch, the fluid port 752 is in fluid communication with the second side772 a of the fluid velocity resistor 470 and the second side 772 b ofthe fluid velocity fuse 480. The fluid pump assembly 750 is configuredto urge fluid flow from the fluid port 751 to the fluid port 752, and tourge fluid flow from the fluid port 752 to the fluid port 751 throughthe fluid velocity resistor 470 and the fluid velocity fuse 480.

In some implementations, the process 800 can include applying electricpower to an electromechanical actuator configured to urge movement ofthe output member. For example, electric power can be applied to themotor 412 to drive extension and/or retraction of the output member 430.

Although a few implementations have been described in detail above,other modifications are possible. For example, the logic flows depictedin the figures do not require the particular order shown, or sequentialorder, to achieve desirable results. In addition, other steps may beprovided, or steps may be eliminated, from the described flows, andother components may be added to, or removed from, the describedsystems. Accordingly, other implementations are within the scope of thefollowing claims.

What is claimed is:
 1. An actuator apparatus comprising: an outputmember configured to actuate between a first positional configurationand a second positional configuration; a source fluid reservoir; a fluidvelocity resistor configured to provide a predetermined resistance tofluid flow; a fluid velocity fuse configured to flow fluid flows havinga first predetermined range of fluid velocities and to block fluid flowshaving second predetermined range of fluid velocities; and a fluidactuator assembly configured to urge fluid flow from the source fluidreservoir through the fluid velocity resistor and the fluid velocityfuse based on actuation of the output member.
 2. The actuator apparatusof claim 1, wherein the fluid velocity resistor is connected in fluidicparallel with the fluid velocity fuse.
 3. The actuator apparatus ofclaim 1, wherein the fluid actuator assembly comprises a fluid pistonassembly comprising a pressure chamber defined by the source fluidreservoir and a piston configured to vary a volume of the pressurechamber based on actuation of the output member.
 4. The actuatorapparatus of claim 3, further comprising a drain fluid reservoir,wherein the fluid velocity resistor and the fluid velocity fuse areconnected in fluidic parallel between the pressure chamber and the drainfluid reservoir, and the fluid piston assembly is configured to urgefluid flow from the pressure chamber to the drain fluid reservoirthrough the fluid velocity resistor and the fluid velocity fuse.
 5. Theactuator apparatus of claim 4, wherein the drain fluid reservoircomprises a fluid pressure assembly configured to urge fluid flow fromthe drain fluid reservoir to the source fluid reservoir.
 6. The actuatorapparatus of claim 5, wherein the fluid pressure assembly comprises afluid chamber defined by the drain fluid reservoir and another pistonconfigured to energize an energy storage member in response to receivingfluid from the fluid actuator assembly, and to urge fluid flow towardthe fluid actuator assembly based on energy recovered from the energystorage member.
 7. The actuator apparatus of claim 1, wherein the fluidactuator assembly comprises a fluid pump assembly configured to bedriven by the output member.
 8. The actuator apparatus of claim 7,wherein the fluid pump assembly comprises a first fluid port in fluidiccommunication with a first side of the fluid velocity resistor and afirst side of the fluid velocity fuse, a second fluid port in fluidiccommunication with a second side of the fluid velocity resistor and asecond side of the fluid velocity fuse, a pump member configured to urgefluid flow from the first fluid port to the second fluid port, and tourge fluid flow from the second fluid port to the first fluid portthrough the fluid velocity resistor and the fluid velocity fuse.
 9. Theactuator apparatus of claim 1, further comprising an electromechanicalactuator configured to actuate the output member.
 10. A method ofcontrolling actuator velocity, the method comprising: urging movement ofan output member of an actuator at a first output member velocity;urging, by a fluid actuator assembly, based on movement of the outputmember at the first output member velocity, fluid flow at a first fluidflow velocity through a fluid velocity resistor configured to provide apredetermined resistance to fluid flow; urging, by the fluid actuatorassembly, based on movement of the output member at the first outputmember velocity, fluid flow at a second fluid flow velocity through afluid velocity fuse configured to flow fluid flows having a firstpredetermined range of fluid velocities and to block fluid flows havingsecond predetermined range of fluid velocities, wherein the second fluidflow velocity is within the first predetermined range of fluidvelocities; permitting, by the fluid velocity fuse, fluid flow throughthe fluid velocity fuse based on the second fluid flow velocity beingwithin the first predetermined range of fluid velocities; urgingmovement of the output member at a second output member velocity,different from the first output member velocity; urging, by a fluidactuator assembly, based on movement of the output member at the secondoutput member velocity, fluid flow at a third fluid flow velocitythrough the fluid velocity resistor; and urging, by the fluid actuatorassembly, based on movement of the output member at the second outputmember velocity, fluid flow at a fourth fluid flow velocity through thefluid velocity fuse, wherein the fourth fluid flow velocity is differentfrom the second fluid flow velocity, and wherein the fourth fluid flowvelocity is within the second predetermined range of fluid velocities;and blocking, by the fluid velocity fuse, fluid flow through the fluidvelocity fuse based on the fourth fluid flow velocity being within thesecond predetermined range of fluid velocities.
 11. The method of claim10, further comprising: resisting movement of the output member at afirst level of resistance based on the first fluid flow velocity and thesecond fluid flow velocity; and resisting movement of the output memberat a first level of resistance based on the third fluid flow velocityand based on the blocking of fluid flow by the fluid velocity fuse. 12.The method of claim 10, wherein the fluid velocity resistor is connectedin fluidic parallel with the fluid velocity fuse.
 13. The method ofclaim 10, wherein: the fluid actuator assembly comprises a fluid pistonassembly comprising a pressure chamber defined by a source fluidreservoir and a piston configured to vary a volume of the pressurechamber based on actuation of the output member; urging, by the fluidactuator assembly, based on movement of the output member at the firstoutput member velocity, fluid flow at the first fluid flow velocitythrough the fluid velocity resistor configured to provide thepredetermined resistance to fluid flow further comprises reducing thevolume of the pressure chamber, based on movement of the output memberat the first output member velocity and urging fluid flow out of thepressure chamber at a first outflow rate; and urging, by the fluidactuator assembly, based on movement of the output member at the secondoutput member velocity, fluid flow at the fourth fluid flow velocitythrough the fluid velocity fuse, wherein the fourth fluid flow velocityis different from the second fluid flow velocity, and wherein the fourthfluid flow velocity is within the second predetermined range of fluidvelocities further comprises reducing the volume of the pressurechamber, based on movement of the output member at the second outputmember velocity and urging fluid flow out of the pressure chamber at asecond outflow rate that is different from the first outflow rate. 14.The method of claim 13, further comprising urging fluid flow to a drainfluid reservoir, wherein the fluid velocity resistor and the fluidvelocity fuse are connected in fluidic parallel between the pressurechamber and the drain fluid reservoir, and the fluid piston assembly isconfigured to urge fluid flow from the pressure chamber to the drainfluid reservoir through the fluid velocity resistor and the fluidvelocity fuse.
 15. The method of claim 14, further comprising urging, bya fluid pressure assembly of the pressure chamber, fluid flow from thedrain fluid reservoir to the source fluid reservoir.
 16. The method ofclaim 15, further comprising energizing an energy storage member basedon fluid flow to the drain fluid reservoir, and wherein urging, by thefluid pressure assembly of the pressure chamber, fluid flow from thedrain fluid reservoir to the source fluid reservoir comprises urge fluidflow toward the fluid actuator assembly based on energy recovered fromthe energy storage member.
 17. The method of claim 10, furthercomprising: pumping, by a fluid pump assembly of the fluid actuatorassembly and configured to be driven by the output member, fluid at afirst pump output velocity based on movement of the output member at thefirst output member velocity, wherein the first fluid flow velocity andthe second fluid flow velocity are based on the first pump outputvelocity; and pumping, by the fluid pump assembly, fluid at a secondpump output velocity different from the first pump output velocity basedon movement of the output member at the second output member velocity,wherein the third fluid flow velocity and the fourth fluid flow velocityare based on the second pump output velocity.
 18. The method of claim17, further comprising: urging, by a pump member of the fluid pumpassembly, fluid from a first fluid port in fluidic communication with afirst side of the fluid velocity resistor and a first side of the fluidvelocity fuse, to a second fluid port in fluidic communication with asecond side of the fluid velocity resistor and a second side of thefluid velocity fuse; and urging, by the pump member, fluid flow from thesecond fluid port to the first fluid port through the fluid velocityresistor and the fluid velocity fuse.
 19. The method of claim 10,further comprising applying electric power to an electromechanicalactuator configured to urge movement of the output member.
 20. Aturbofan engine system comprising: a turbofan engine; a nacellesurrounding the turbofan engine and defining an annular bypass ductthrough the turbofan engine to define a generally forward-to-aft bypassair flow path; a thrust reverser having at least one output member,movable to and from a reversing position where at least a portion ofbypass air flow is reversed; an actuator coupled to the at least oneoutput member to move the at least one output member into and out of thereversing position; a source fluid reservoir; a fluid velocity resistorconfigured to provide a predetermined resistance to fluid flow; a fluidvelocity fuse configured to flow fluid flows having a firstpredetermined range of fluid velocities and to block fluid flows havingsecond predetermined range of fluid velocities; and a fluid actuatorassembly configured to urge fluid flow from the source fluid reservoirthrough the fluid velocity resistor and the fluid velocity fuse based onactuation of the output member.